Tails from a wild metropolis

Main menu

Category Archives: sparrow

A spotted towhee caught on a fast-food run, and not particularly happy about it.

Supermarket tabloids love just-like-us features so they pay paparazzi top dollar to catch somebodies acting like nobodies. Today I’m focused on the Towhees. They like to keep a low profile but I’m a pro and I know how to find them.

First Rule of Papping: Ya can’t tell the players without a scorecard! It also helps to know the aliases they use to create confusion and avoid detection. See, for a long time all the Towhee’s identified as Team Pipilo. Several years ago, however, about half of them left (were removed, actually) to form Team Melozone. Maybe the rift was media-created (fake news, so sad), or maybe the less flamboyant Towhees felt overshadowed by their more colorful and fashion-forward cousins… who knows? Towheestas, as their fandom are known, love to argue over the distinctions between and relative merits of the two tribes, as well as who should be a P and who definitely qualifies as an M.

Currently, Team P include the Collareds (P. ocai), the Green-taileds (P. chlorurus), the Easterns (P. erythrophthalmus), and the Spotteds (P. maculatus), but not so long ago both the Easterns and Spotteds were using the tag Rufous-sided (the Easterns got full custody of P. erythrophthalmus). Spotteds are also referred to in some circles as The Avians Formerly Known as Oregon or Socorro.

Similarly, and to keep things even-steven, Team M also has four members: the Aberts’ (M. aberti), the White-throateds (M. leucotis), the Canyons (M. fusca), and the Californias (M. Crissalis). Oh, but the Canyons and the Californias used to be one big happy tribe, the Browns, even though the Aberts’ and the Californias are probably closer relatives.

Got it all straight? Yeah, it’s a complicated family tree — that’s show biz. Try keeping track of the rest of the Sparrows, not to mention the Barrymores, the Fondas, and the Coppolas.

Second Rule of Papping: Zoom in on the habitat. Finding out where your luminary lives is a crucial datapoint. Some Towhees prefer to be on the right side of the continent (Easterns), some are Westerners (Californias, Green-taileds, and Spotteds), and there’s some who meet in the middle. Others Towhees prefer the Southwest (Canyons and Aberts’), or even south of the border in Mexico (Collareds & White-throateds).

Towhees do household chores, just like us!

When it comes to choosing a home base, the Easterns and Spotteds will always opt for a ground-floor unit, if available, ideally tucked in next to a log or of clump of grass to provide some privacy, but they’ll tolerate the higher perches (shrubs) preferred by the Californias, Canyons, and Green-taileds. The Aberts’ are the only Towhees who like to live in a tree-top high-rise. Not much is know about where the Collareds and White-throateds homestead because they’re a secretive bunch who’ve put down roots far from the limelight’s glare, in the more rural setting of Mexico’s mid-to-high altitude subtropical and tropical pine-oak forests. They’re a rare and lucrative shot but too remote for run-and-gun photography.

A Spotted spotted at the spa.

Improve your chances by becoming a regular at all of the places your subjects like to eat, including the local hipster farmers markets and upscale grocers, where they shop for household supplies, as well as favorite watering holes and spas. If you can get a neighborhood exposure you’re golden because that’s where life gets real. As the playground K-I-S-S-I-N-G song tells it, first comes love, then comes marriage, then comes baby in a $700 Bugaboo carriage. Actually, these days marriage is an option, not a certainty. Regardless of the parents’ living arrangements and legal status, or lack thereof, nest/crib beta is pivotal for a paparazzo because editors drool when there are kids in the picture — Mommy & Me outings are always Money Shots.

A California towhee takes her mini-me out for lunch.

Third Rule of Papping: Know your subject inside as well as out. In other words, not just their look but the idiosyncratic behaviors that will tip you off to their presence, even when they’re not wearing breeding plumage. For example, you’ll want to know that all the Towhees like to forage for food using a unique two-footed backward hop, followed by a pert bend-and-snap. Well, I assume this includes those camera-shy Collared and White-throateds but who the hell knows. If the pickin’ are slim, or maybe too predictable, Spotteds will scan the shrubbery for snacks, and the Aberts’ have been known to poke around under the bark near the bottom of tree trunks for some grub.

Family comes first for the Canyons and Green-taileds, who have a reputation for forming long-term, monogamous pair-bonds. If a Green-tailed mom senses danger, she’ll bravely flee from home on foot with a conspicuously raised tail to attract and distract the predator’s attention from her children.

A California fascinated with its reflection in a window.

It will probably come as no surprise, that the Cali Crew has an ongoing love/hate relationship with their image — you’ll see them in front of a freshly washed window, handy car mirror, or any other reflective surface checking out their visuals or talking to themselves in a very critical, territorial tone. They’re not crazy, just a little left of center. They like to chill in stands of poison oak, feeling all cutting edge because this hangout hasn’t been “discovered” yet, gobbling up the pale berries as if they were caviar.

Last, but not least… shut up and get the shot. Sure, the relationship between some celebrities and the paparazzi is symbiotic— they get publicity, you get residuals. Towhees don’t play that. If you want to be successful with this dynasty you’ll stay quiet, blend into the scenery, keep your eyes open, and your finger on the trigger. Be the early bird that catches the worm. Not that Towhees are worms. Far from it. Truth is, they’ll eat that worm for breakfast… and you could get it all on film (or a memory card).

When you’re trying to stay cool without air conditioning, it helps to carry a radiator on your face, large or small (Photos: Ame Otoko and Cephas, Creative Commons license).

.

A scientists’ work is never done.

That’s because there’s always another layer to peel away, another stone to turn, another angle from which to view the situation. Case in point—nearly 200 years ago, Charles Darwin made the connection between the size and shape of a finch’s beak and the availability of the seeds they eat; to this very day, no one has been able to produce evidence that undermines his observation and the conclusions he drew from them.

But what if there’s more to a beak than meets the eye?

That’s the question raised by Russell Greenberg of the Smithsonian Conservation Biology Institute. His theory—that beak size may also be an adaptation to temperature regulation and water conservation—has been bolstered by data from two recently published studies. [Data collected, in part, by a newly minted PhD named Ray Danner. Ray just happens to be a member of my own adopted extended family, and if that name sounds vaguely familiar… well, regular NDN readers may remember that not too long ago I was bragging about another member of this ornithological power couple, Ray’s wife, Dr. Julie Danner.]

Some years back, Greenberg noticed a difference in size between the beaks of sparrows living in salt marshes and those of sparrows settled just a kilometer or two further inland. Then a paper published in 2009 reported toco toucans (Ramphastos toco) may lose as much as 60% of their body heat through their long bills, based on thermal imaging and similar to the role played by the large ears of both elephants (Elephantidae) and jackrabbits (Lepus spp.). While many ecologists assumed toucans were a special case, Greenberg wondered—might other birds have evolved larger or smaller beaks to discharge or conserve heat as well?

He chose to test his hypothesis by applying thermal imaging to a subject with a much less prominent proboscis—the song sparrow (Melospiza melodia). Native to North America, everything about these feathered minstrels is miniature compared to their South American kin. The toucan weighs in at 1-2 pounds (the large bill doesn’t actually tip the scale as much as you might think since it’s mostly hollow) while at 0.4—1.9 ounces the song sparrow is definitely a featherweight.

In the first study, two subspecies were examined. On average, the beak of an Atlantic song sparrow was found to have 17% more surface area than that of the eastern song sparrow, although both birds have similarly sized bodies. Based on the Greenberg team’s calculations, the Atlantic sparrow loses 33% more heat than it’s inland neighbor. The finding suggests beaks may play a role in thermoregulation for a wide variety of bird species.

The ability to stay cool when the ambient temperature rises is critical to survival, but how one gets rid of the excess heat is just as important. Birds don’t sweat—they pant… and lose not just heat but water in the process. This summer, residents across the U.S. have been reminded just what a precious resource water can be, and never more so than for all the creatures without easy access to a faucet. Greenberg and his colleagues suggest that a bird’s beak can function like a radiator, releasing heat without losing water. The Atlantic sparrow’s larger bill saves the bird about 8% more water than the smaller beaked eastern sparrow. That may not sound like much but during a hot, dry summer it could be a significant survival advantage.

The second study examined museum specimens of song sparrows collected on the other side of the continent, along the California coast. Sure enough, as maximum temperatures increase, so did beak size… with one caveat. When the maximum temperature was higher than 98°F (37°C) beaks got smaller… just as was predicted by the original hypothesis. You see, if you took a song sparrow’s temperature the thermometer would read about 105°F (41°C). When the air temperature exceeds the bird’s own temperature, as it does in some regions, a larger beak could actually begin to absorb heat.

While the Smithsonian group has demonstrated a connection between climate and beak size, there’s still plenty of work to be done. For the new hypothesis to garner support, scientists need to see data that ties survival of wild birds to beak size-related heat dissipation.

Meanwhile, the fact that diet influences beak size and shape hasn’t changed—Darwin can continue to rest in peace. But as so often is the case, the more we discover the more we realize just how rich and complex this world and its inhabitants are … even an Earthling as seemingly plain and simple as a sparrow.

.

This blog, like so many activities that foster support and appreciation of the natural world, is a labor of love. If you’ve enjoyed learning about the creatures who share our built environment, consider becoming an NDN Benefactor with a donation of any amount you’re inspired to give. If you’d like to find a little Next-Door Nature surprise in your inbox just click the Subscribe! button in the upper right-hand corner of this page and receive notifications of new posts!

A white-crowned sparrow trying to get a date (Photo: KaCey97007, Creative Commons license)

.

How can one small voice cut through the cacophony of modern metropolitan life? A recently published study, combined with some earlier work, suggests that contrary to what you might assume, the secret to city communication isn’t shouting.

Urban background noise is heavily weighted toward the lower sound frequencies of 20 to 200 Hz—think diesel engines (50-60 Hz). That’s not to say there aren’t a lot of higher frequency noises in the concrete jungle but, compared to say, the rain forest’s tenor voice, cities sing baritone… and with enough projection to reach the last row of the balcony. Depending on the location and the time of day, your city may be belting out it’s theme song at anywhere from ~45-90 decibels (dB). Ever try to tweet over a lawn mower (and I don’t mean with your smart phone)?

People who haven’t yet experienced any hearing loss can detect activity in the 20 to 20,000Hz range. The faintest sounds we’re likely to hear register at about 0 dB. By 120 db we begin to experience discomfort or even pain. Now, as someone who loves to listen to nearly every kind of music, laughter in all its forms, Japanese prayer bells playing with a breeze, and rain bouncing on a tin roof, I’d be the first to agree that the human ear is a marvel. But compared to many of our fellow Earthlings, it’s… well, it’s pitiful. My wire fox terrier puts me to shame, easily picking up sounds from 40-60,000 Hz. The super-sensitive hearing of a bat, used for echolocation, ranges from 20-120,000 Hz.

common blackbird

According to the ever-useful Birder’s Handbook, we have more auditory commonality with birds, whose ability to discriminate between frequencies and degrees of loudness is on a par with our own. So perhaps we would be well served to take a page from the songbird songbook when trying to be heard in our rapidly urbanizing modern life. Researchers at the Universities of Copenhagen and Aberystwyth found that great tits (Parus major) living in urban habitats sing at a significantly higher frequency than their rural relatives. This finding coincides with previous studies reporting the same phenomenon for house finches (Carpodacus mexicanus), song sparrows (Melospiza melodia), white-crowned sparrows (Zonotrichia leucophrys), dark-eyed juncos (Junco hyemalis), and common blackbirds (Turdus merula).

European robin

Of course, going all Bee-Gees isn’t the only way a guy can get some attention from the talent scouts. A 2007 study from the University of Sheffield found that European robins (Erithacus rubecula) living downtown changed their performance times, from doo-wopping during the day to crooning almost exclusively after sundown when the din dies down a bit. In Berlin, nightingales (Luscinia megarhynchos) take the less subtle approach and just turn up the volume, at least on weekdays. But there’s a price to be paid for setting the amps to 11—a greater metabolic demand and more attention from predators. By broadcasting on a different frequency, some city songbirds have stumbled onto a low-risk solution to a major challenge of city life.

song sparrow

There’s incentive for avian adaptation (let’s not call it selling out) to make it onto the airwaves. You see, in the bird world the divas are all, um… divos. No, they don’t wear red plastic wedding cake hats and ill-fitting 1980s MTV fashion—that’s Devo. Let me put it another way: boy birds are the rock stars, girl birds are the groupies. Males warble (or learn to shred the guitar, or maybe groove a bass line) to get noticed by the ladies. If a gal likes a guy’s song she’ll hook up with him and probably become his baby-mama. But there’s a lot of competition out there and before you can score, you’ve gotta get heard.

Hey, singing falsetto to some chick may not be the most macho thing a fellow can do, but it beats spending Saturday night getting drunk at the karaoke bar with your buddies and going home alone.

.

Start your day with a little Next-Door Nature—click the “subscribe” link in the upper right-hand corner of this page and receive notifications of new posts!

Male rufous-collared sparrows know how to put just the right spin on a tune to woo the local girls (Photo: Dario Sanches, Creative Commons license)

.

One of the things I like best about traveling is hearing different accents, turns of phrase, the variations in cadence and rhythms of speech unique to a specific place. Now that there’s a Starbucks on nearly every commercial district corner, and big box stores are shading out the retail undergrowth, it can be easy to forget you’re away from home until you exchange verbal pleasantries with a local.

Biologists have known for some time that dialects aren’t limited to the human population. Many wild bird species have them too. It can be harder for the untrained human ear to hear, but spectrograms of bird songs show distinct regional, local, and individual variation.

Recently, I learned that a member of my own extended family-of-choice has been traveling to Ecuador to study the dialects of rufous-collared sparrows (Zonotrichia capensis). In the process, Julie Danner—the new wife of my non-biological sister’s nephew—has discovered something about Andean sparrows, as they’re also known, that made even the New York Times take notice: Sparrow chicas are more likely to hook up with homeboys than with chicos who don’t sound like they’re from the ‘hood.

Or, in the language of a scientific journal such as The American Naturalist, where Julie, her husband Ray Danner, and their colleagues at Virginia Tech published their research results, female sparrows “gave significantly more copulation solicitation displays in response to their local dialect than to the song dialects from a population on the other side of an Andean pass (25 km away).”

The rufous-collared sparrow is the only tropical member of this genus and a close relative of the white-crowned sparrow (Zonotrichia leucophrys) found throughout most of North America. Initially, Julie studied two groups of birds but later expanded to eight populations. Her research suggests as little as 15 miles is enough to produce bird “accents.”

Recordings of male songs were made at varying distances from a home territory, along with the songs of other bird species. Then Julie put individual females into a holding cage and played the recordings.

“I found out that females distinguish between dialects and prefer the local dialect,” she explains.

Bird dialects seem to be formed by individual birds making slight errors in reproducing the characteristic tune of their species. These errors are picked up by new generations of young males, who don’t know any better, when they’re learning to sing love songs.

Scientists are pretty good describing what is happening in the world (e.g., female sparrows prefer local males) but it’s much harder to explain why. Is there any benefit to females and their offspring when they choose the boy next-door? Julie doesn’t know, but she’s come up with an educated guess.

“A male singing local song could be better adapted to the local environment. He may have better resistance to certain local parasites. A local male may just do better in that environment.” If that’s true, it could increase the likelihood that a female’s offspring will survive.

What’s true for birds is not necessarily true for those who study birds. Julie, who started her doctoral work in 2006 and hopes to finish up next year, is a Connecticut native. Her husband was born and raised over 1000 miles away, in my hometown of St. Louis, Missouri.